[PATCH v5 11/17] iommu/arm-smmu-v3: Remove arm_smmu_master->domain

Jason Gunthorpe
2024-02-06T16:15:54Z

Introducing global statics which are of type struct iommu_domain, not
struct arm_smmu_domain makes it difficult to retain
arm_smmu_master->domain, as it can no longer point to an IDENTITY or
BLOCKED domain.

The only place that uses the value is arm_smmu_detach_dev(). Change things
to work like other drivers and call iommu_get_domain_for_dev() to obtain
the current domain.

The master->domain is subtly protecting the domain_head against being
unused, change the domain_head to be INIT'd when the master is not
attached to a domain instead of garbage/zero.

Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Moritz Fischer <moritzf@google.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 26 ++++++++-------------
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 1 -
2 files changed, 10 insertions(+), 17 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 133f13f33df124..a98707cd1efccb 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2560,19 +2560,20 @@ static void arm_smmu_disable_pasid(struct arm_smmu_master *master)

static void arm_smmu_detach_dev(struct arm_smmu_master *master)
{
+ struct iommu_domain *domain = iommu_get_domain_for_dev(master->dev);
+ struct arm_smmu_domain *smmu_domain;
unsigned long flags;
- struct arm_smmu_domain *smmu_domain = master->domain;

- if (!smmu_domain)
+ if (!domain)
return;

+ smmu_domain = to_smmu_domain(domain);
arm_smmu_disable_ats(master, smmu_domain);

spin_lock_irqsave(&smmu_domain->devices_lock, flags);
- list_del(&master->domain_head);
+ list_del_init(&master->domain_head);
spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);

- master->domain = NULL;
master->ats_enabled = false;
}

@@ -2626,8 +2627,6 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)

arm_smmu_detach_dev(master);

- master->domain = smmu_domain;
-
/*
* The SMMU does not support enabling ATS with bypass. When the STE is
* in bypass (STE.Config[2:0] == 0b100), ATS Translation Requests and
@@ -2646,10 +2645,8 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
case ARM_SMMU_DOMAIN_S1:
if (!master->cd_table.cdtab) {
ret = arm_smmu_alloc_cd_tables(master);
- if (ret) {
- master->domain = NULL;
+ if (ret)
goto out_list_del;
- }
} else {
/*
* arm_smmu_write_ctx_desc() relies on the entry being
@@ -2657,17 +2654,13 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
*/
ret = arm_smmu_write_ctx_desc(master, IOMMU_NO_PASID,
NULL);
- if (ret) {
- master->domain = NULL;
+ if (ret)
goto out_list_del;
- }
}

ret = arm_smmu_write_ctx_desc(master, IOMMU_NO_PASID, &smmu_domain->cd);
- if (ret) {
- master->domain = NULL;
+ if (ret)
goto out_list_del;
- }

arm_smmu_make_cdtable_ste(&target, master);
arm_smmu_install_ste_for_dev(master, &target);
@@ -2693,7 +2686,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)

out_list_del:
spin_lock_irqsave(&smmu_domain->devices_lock, flags);
- list_del(&master->domain_head);
+ list_del_init(&master->domain_head);
spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);

out_unlock:
@@ -2894,6 +2887,7 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
master->dev = dev;
master->smmu = smmu;
INIT_LIST_HEAD(&master->bonds);
+ INIT_LIST_HEAD(&master->domain_head);
dev_iommu_priv_set(dev, master);

ret = arm_smmu_insert_master(smmu, master);
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index cbf4b57719b7b9..587f99701ad30f 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -696,7 +696,6 @@ struct arm_smmu_stream {
struct arm_smmu_master {
struct arm_smmu_device *smmu;
struct device *dev;
- struct arm_smmu_domain *domain;
struct list_head domain_head;
struct arm_smmu_stream *streams;
/* Locked by the iommu core using the group mutex */
--
2.43.0